Aircrafts that can be used to extinguish fires are known in the art. Examples of such aircrafts are amphibious Canadair forest fire fighter. These so-called “Canadair” aircrafts are dedicated to fighting forest fires or wildfires and search and rescue in case of disaster on sea, due to the ability to land on water surface. These aircrafts are able to fill the installed water tanks while flying over a body of water with the hull of the aircraft skimming the water surface. They can for example fill the water tanks with 6100 liter of water in 12 seconds. To the taken in water additives can be added such as foam forming compounds, or gel to form a liquid fire suppressant. The additives improve the fire suppressing action. After taking in water, the aircraft can take off, fly to the forest fire and drop the content of the water tanks on or near the burning area while flying at low altitude.
By repeating this manoeuvre the forest- or wildfire can be extinguished. A tactical way of firefighting is to spread a wide path or blanket of liquid fire suppressant i.e. water in front of a forest fire by means of multiple droppings, blocking the way for the forest fire to spread out in the direction of the wind.
A disadvantage of such aircrafts is that they are dedicated to this activity and can only be used for extinguishing fires and rescues on high sea. Furthermore they need to contact the water, and usually have only a limited capacity of about 6000 liters of water to release above a fire.
Conventional, non-amphibious aircrafts which contain water tanks, so-called airtankers, may have a larger storage capacity (about 10.000-30.000 liters), but they are not equipped to pick up water from water surfaces like sea, rivers and lakes. They generally need to land at an airport, refill the water tanks and take off again. This takes a large amount of time and only one run and drop of liquid fire suppressant can be achieved per hour. In addition the fuel cost is higher and an efficient method of extinguishing of forest fires (total cost/liters per hour) cannot be reached.
In the art, for example as described in British published patent GB2163710, aircraft are known which are equipped with apparatus for scooping up water. The described aircraft has a boom pivoted at its forward end to the underside of the aircraft's fuselage and having at its rear end a scoop connected via a duct in the boom to a water storage tank mounted in the fuselage. When the aircraft is flying closely above the surface of a body of water, the boom may be lowered to dip the scoop into the water to thereby refill the tank. The scoop can be equipped with a hydrofoil to guide the scoop through the water surface. Such scoop and hydrofoil however have an undefined position with respect to the water surface and may exhibit uncontrolled downward movement when pulled through a water surface, thereby endangering the aircraft to be pulled down and its pilot.